Analysis of the Design and Application of a Novel CT Secondary Cable Line Calibrator

With the rapid development of electrical power systems,ensuring the accuracy and reliability of power transmis-sion has become particularly crucial.The secondary cable line calibrator for current transformers(CT)plays an essential role in calibrating electrical power systems.It is not only related to the safe operation of the system but also directly im-pacts the accuracy of energy metering.This study aims to design and analyze an efficient CT secondary cable line calibra-tor to explore its application effects in the power system.By thoroughly analyzing the characteristics of CT secondary ca-ble lines and the design requirements of the calibrator,this paper proposes an innovative design scheme for the calibrator.This device demonstrates significant effects in enhancing the accuracy and stability of power system calibration,providing robust technical support for the optimization and upgrade of the power system.This research not only offers a theoretical basis and practical guidance for the design and application of CT secondary cable line calibrators but also contributes new ideas and methods for the precise calibration and efficient management of the power system.

Design and manufacture of a 100 kA coaxial pulsed power cable for plasma generator and PPS in ETC guns

Based on our previous pulsed current and internal overvoltage test data and the experience of common commercial high power cables,a 100 kA coaxial pulsed power cable is designed and manufactured to adapt the coaxial electric energy breech transmission between the plasma generator and the pulsed power supply(PPS) in electrothermal-chemical(ETC) guns.The index parameters are analyzed and determined.Semi-conductor layers and a shield stiffener are introduced to prevent the deformation and burst of the pulsed power cable structurally.The semi-conductor layer can eliminate the air gap and balance the electric field in the cable.The shield stiffener can multiply the mechanical strength to restrain the strong electrodynamic force produced by the core dislocation of the outer conductor.The multi-coupling of electromagnetic field,stress field and thermal field analysis are established to assist in aided design of electrical strength,mechanical strength and temperature rise characteristics.Both a DC voltage withstand test and pulsed discharge tests are introduced to verify and inspect the performance and dynamic response of the pulsed power cable.The 25 kV/5 min DC voltage withstand test result shows that the sample leakage current is nearly 3 μA and no abnormal phenomena of the pulsed power cable sample occurred.The pulsed discharge tests show that the sample can sustain the 100 kA peak current.Furthermore,this 100 kA coaxial pulsed power cable can satisfy the ETC test requirements.

Study on 10 kVDC Powered Junction Box for A Cabled Ocean Observatory System

A cabled ocean observatory system that can provide abundant power and broad bandwidth communication for undersea instruments is developed. A 10 kV direct current (kVDC) with up to 10 kW power, along with 1 Gigabit/sec Ethernet communication, can be transmitted from the shore to the seafloor through an umbilical armored cable. A subsea junction box is fixed at a cable terminal, enabling the extension of up to nine connections. The box consists of three main pressure vessels that perform power conversion, power distribution, and real-time communication functions. A method of stacking modules is used to design the power conversion system in order to reduce the 10 kV voltage to levels that can power the attached instruments. A power distribution system and an Ethernet communication system are introduced to control the power supply and transmit data or commands between the terminals and the shore station, respectively. Specific validations of all sections were qualified in a laboratory environment prior to the sea trial. The ocean observatory system was then deployed at the coast of the East China Sea along with three in situ instruments for a 14-day test. The results show that this high voltage-powered observatory system is effective for subsea long-term and real-time observations.

Scheme of long distance power supply for electrified railway traction network based on traction cable

Purpose–The traction cable is paralleled with the existing traction network of electrified railway through transverse connecting line to form the scheme of long distance power supply for the traction network.This paper aims to study the scheme composition and power supply distance(PSD)of the scheme.Design/methodology/approach–Based on the structure of parallel traction network(referred to as“cable traction network(CTN)”),the power supply modes(PSMs)are divided into cableþdirect PSM and cableþautotransformer(AT)PSM(including Japanese mode,French mode and new mode).Taking cableþJapanese AT PSM as an example,the scheme of long distance power supply for CTN under the PSMs of co-phase and out-of-phase power supply are designed.On the basis of establishing the equivalent circuit model and the chain circuit model of CTN,taking the train working voltage as the constraint condition,and based on the power flow calculation of multiple train loads,the calculation formula and process for determining the PSD of CTN are given.The impedance and PSD of CTN under the cableþAT PSM are simulated and analyzed,and a certain line is taken as an example to compare the scheme design.Findings–Results show that the equivalent impedance of CTN under the cableþAT PSM is smaller,and the PSD is about 2.5 times of that under the AT PSM,which can effectively increase the PSD and the flexibility of external power supply location.Originality/value–The research content can effectively improve the PSD of traction power supply system and has important reference value for the engineering application of the scheme.

Online Loss Parameters Diagnosis Device Development of Power Cable Insulation

In southern China, power cable lines often running in water, and the state of XLPE insulation is difficult to detection effectively. This paper studied loss parameters online diagnosis technology of power cable insulation. An online loss parameters diagnosis device was development, which consists of current comparator, voltage controlled current source (VCCS), standard capacitor, GPRS wireless transmission system, control system and the data processing unit. 108 cables were detected using this device, and it was found out that one cable appeared to middle aging and eight cables appeared to slight aging. The butterfly water trees were observed in middle aging cable, which prove the effectiveness of online testing in the loss current measurement.

A 4m 2kA HTS Power Cable System

A high temperature superconductor (HTS) cable system of both a length of 4 metreand a normal current of 2 KA with terminations and a cooling system has been built up andtested.The cable conductor was made of Bi-2223 tape.A space maintained vacuum betweentwo corrugated stainless steel tubes functions as the cryostat surrounding the superconductor.Aseries of tests were carried out to verify the functions of the system.The important data obtainedcan be used to make longer HTS cable systems.

Analysis of DC Power Transmission Using High T_c Superconducting Cables

A conceptual superconducting DC cable model is designed and its magnetic fields distribution is analyzed with Ansoft/Maxwell soft. A DC Power transmission system is also studied by using the Matlab/Simulink. With the DC Line and AC Ground Fault, the system losses analysis is introduced.The analysis results mainly include the magnetic fields distribution of the HTS cable model with Ansoft/Maxwell, the system loss, the DC Line and AC Ground Fault with Matlab/Simulation.

HTS Power Cable Developed

With the support of the National Center for R&D on Superconductivity, a 6m high T_c superconducting (HTS) power cable has cartied a current of 1473 A successfully at the Institute of Electrical Engineering (IEE), CAS. In 1998, a one-meter-long, 1000A HTS power cable prototype was developed successfully by

Power over Cable:整合数据传输与供电,单一缆线解决工业视觉应用的需求

所有的工业机器视觉设备都需要依赖图像数据传输与电源供应,而且大多数的工业相机都需要使用两条缆线,一条用于传输数据,另一条则是电源线,这意味着使用者必须多花一倍安装与维护缆线的成本,同时缆线故障的机率也增加一倍。随着工业机器视觉市场从模拟跨入数字相机后,如何通过"Power over Cable"供电型接口简化安装、节省空间以及降低成本,成为工业机器视觉应用中最新的话题。

Aging Characteristics of XLPE Insulation of 110 kV Cables in the Initial Stage of Operation

The aging characteristics of the XLPE insulation of 110 kV power cables in the initial stage of operation are studied in this paper.The XLPE insulation from cables with different running time was tested by using electrical and physicochemical methods,from which the degradation state of XLPE under multiple stresses during operation was derived.The broadband dielectric spectrum test taken from 10–1 to 10^(6) Hz showed that the dielectric constant and dielectric loss of the XLPE insulation first decrease and then increase with the increase of cable running time,which show obvious variation until 10 years of operation.The AC breakdown strengths of the XLPE insulation of operated cables with the service year no longer than 10 years were higher than that of new cables.The mechanical properties of the XLPE insulation showed no dependence with the cable running time.The crystallinity and perfection of the crystallization area were found to be enhanced during operation and the polar functional groups inside the XLPE insulation were found to be determined not only by the cross-linking by-products but also by the oxidation process during cable operation.The experimental results in this paper are important for improving the operation reliability and reducing the maintenance costs of the cables.

Live-Grid Operation and Maintenance of the 35 kV/121 MVA Superconducting Cable System

A 33.5 m, 35 kV/121 MVA, three-phase, warm dielectric HTS power cable system was successfully installed and activated in China Southern Power Grid at the Puji substation in Kunming on April 19th of 2004, supplying electricity to four industrial customers (including two metallurgical refineries) and a residential population of about 100000. In this paper, we give an update on the operation and maintenance status of the system and comments on reliability issues. We conclude that the superconducting cable system is currently quite robust and feasible for particular utility applications, and it will be improved by advancement in cryogenic equipment and system technology.

氢闸流管驱动三同轴电缆Blumlein线的kHz重频脉冲功率源

闪光X射线摄影技术在军事和民用等多个领域具有重要场景。针对重频直线感应加速器高重频的要求,提出了基于氢闸流管驱动三同轴电缆Blumlein线的脉冲功率源方案,设计和研制了一种三同轴电缆,研究了氢闸流管的导通特性,搭建了氢闸流管驱动三同轴电缆Blumlein线脉冲功率源的验证平台,开展了kHz重频脉冲功率源实验研究,以及kHz重频脉冲功率源驱动重频感应腔的实验研究,结果表明:基于氢闸流管驱动三同轴电缆Blumlein线脉冲功率源实现了波形品质优异的kHz重频方波脉冲输出。

基于免疫Agent的电力电缆线路故障检测系统

为区别故障信号、非故障信号,实现对电缆线路故障的准确检测,设计了基于免疫Agent的电力电缆线路故障检测系统。利用前端检测电路为故障分析模块、测距方式切换模块提供电量传输信号,完成系统前端检测装置的连接。按照免疫Agent检测原理提取电力电缆线路故障信号的特征,联合已获取信号对象,求解检测插值指标的具体数值。结合各级硬件设备结构,完成系统设计。实验结果表明,该系统可同时检测波频为10~20 Hz、40~50 Hz、60~70 Hz的故障信号与波频为20~30 Hz、30~40 Hz、50~60 Hz的非故障信号,可以在精准辨别故障与非故障信号的同时,实现对电力电缆线路故障的准确检测。

井下电力电缆故障定位研究

针对传统井下电力电缆故障定位方法依赖主观参数选择和抗噪性能较差,无法满足强噪声背景下井下电力电缆故障精确定位要求的问题,提出了一种基于樽海鞘群算法(SSA)优化变分模态分解(VMD)并结合改进型Teager能量算子(NTEO)的井下电力电缆故障定位方法。针对VMD在信号分解上存在的模态混叠、过分解和欠分解问题,采用SSA以模糊熵为适应度函数对VMD模态数K和惩罚因子α2个参数进行优化,得到更能反映故障特征信息的本征模态函数;采用NTEO对本征模态函数进行首波波头标定,得到首末两端的波头到达时刻,根据双端测距法得出故障位置。采用PSCAD/EMTDC进行井下电力电缆故障仿真,模拟具有强背景噪声的井下故障信号,结果表明:①在理想电流信号中加入9,12 dB噪声后,SSA-VMD的信噪比最低,皮尔逊相关系数最大,说明SSA-VMD在最大程度降噪的同时,能很好地保留信号的特征信息。②在不同过渡电阻下,SSA-VMD-NTEO的定位精度较高。③在不同故障相角下,SSA-VMD-NTEO在采样点上出现不同,但定位位置没有改变,依旧保持较高的定位精度。④在不同故障距离下,SSA-VMD-NTEO均能保证较高的定位精度。⑤在井下较大噪声和10 MHz采样频率下,SSA-VMD-NTEO较小波模极大值和VMD+NTEO 2种方法的定位精度具有明显优势。

基于代理模型的电力电缆温度场快速计算方法及其应用

电缆内部温度是电缆管理的重要参数,针对高精度数值计算和实验测量均不能快速准确预测电缆内部温度的问题,提出一种基于多物理场仿真数据构建代理模型,并基于代理模型实现电缆内部温度场快速计算的方法。以110 kV单芯高压电缆为例,首先对比拉丁超立方设计和最大最小思想优化的拉丁超立方方法构造样本空间的效果,选取最优采样方案,再通过径向基神经网络构建代理模型,以环境温度和载流量为变量构建温度数据集进行测试,进一步通过粒子群算法对代理模型进行优化,最后利用网格节点数据使温度场分布可视化。对比110 kV单芯高压电缆内部温度场计算结果,表明所提的基于代理模型的电力电缆温度场快速计算方法具有较高的精度和效率。

地面装备电源变换系统高低压线缆串扰仿真研究

电源变换系统中功率器件如MOSFET和IGBT开关管的高速切换将产生高幅值和宽频段的电磁干扰,是电动车辆最为常见也无法避免的电磁干扰源。同时,互连线缆是机电设备传递信号和能量的载体,是实现设备功能不可或缺的组成部分,线缆的天线效应使其成为设备产生电磁干扰的主要途径,是系统电磁兼容问题的主要根源之一。为了分析高压电源变换系统对低压控制系统的电磁耦合,以某典型地面装备电源变换系统IGBT开关管产生的脉冲宽度调制波(PWM波)作为电磁干扰源,以实装线缆作为分析对象,构建高低压线缆串扰模型,仿真分析不同线缆对地距离、线缆间距条件下单线、屏蔽线、双绞线等多类低压线缆的近端串扰电压,得出低压线缆的抗干扰性,为系统线缆的布线提供指导。

基于有限元法的谐波作用对电缆及其接头的影响研究

现有关于电缆及其接头温度的研究大多按照基波情况考虑,大量非线性负载的使用使输电线路中的谐波含量显著增加,谐波对电缆及其接头附加损耗与温升的影响不容忽视。文中以64/110 kV单芯电缆及预制式电缆接头为例,建立了电缆及其接头的有限元仿真模型,基于电磁-热耦合法,分析了谐波含量与谐波次数对电缆及其接头的影响,并引入等效电流因数,实现多次谐波共存环境下对电缆发热损耗及温度的快速计算。仿真结果表明:谐波含量与谐波次数均会影响电缆的损耗及温度,谐波可能导致电缆接头在压接钳处形成过热点,加速绝缘老化;引入等效电流因数法在估算多次谐波共存环境下的电缆温度具有较高精度。该研究对谐波环境下电缆及其接头的设计、运行温度预测及热老化寿命评估提供了依据。

内热源影响下高压电力电缆着火机制

为探究高压电力电缆因过载或短路且线芯发热影响下的着火机制,使用加热棒模拟电缆内部故障热源,并开展电缆着火试验,分析内热源功率及电缆线芯截面积对电缆温升、着火时间等着火关键参数的影响,发现电缆从被加热至着火到燃烧的全过程可分为初期加热、热解气体逸出、着火、燃烧及熄灭4个阶段。结果表明:绝缘层熔融物的滴落会导致火焰形态发生变化,电缆各结构层表面温度的升温速率随内热源功率的增加及与内热源表面距离的减小而增大,功率的增加弱化了电缆线芯截面积对各层升温速率的影响;电缆的着火时间与内热源功率呈线性递减的关系。

基于PT-PFM激励阻抗谱数字重构的电缆故障诊断定位

由于传统频谱测试仪器增益带宽积有限,高频区间内输出电压过低,在针对长距离电缆测试时信号衰减较为严重,导致阻抗谱在高频区间内存在一定失真问题。该文提出一种基于伪梯形波激励阻抗谱数字重构算法的电缆故障诊断定位算法。分析不同故障类型下电力电缆的局部故障阻抗对电缆输入阻抗谱的影响规律、首端激励电压信号的衰减特性和不同电压幅值的功率传输特性。设计一种基于Si C高速逆变器的大容量伪梯形励磁系统,用于测量最高频率7 MHz的阻抗谱信息,利用阻抗谱数字重构方法实现0.1 Hz~60 MHz宽频区间的全覆盖。与传统的低压正弦激励相比,采用该时空转换函数的定位结果具有更小的区间振荡和更快的收敛速度。缺陷定位精度提高了80%,验证了该方法的有效性和准确性。